Persons afflicted with cataracts in one or both eyes must undergo surgery to remove the cataracts. Prior to such surgery, the cataract sufferer finds that the acuity or focusing ability of his eye deteriorates over a period of time. Generally, prescription lenses are worn to provide the best acuity or focusing. However, this does not fully correct the imaging capability of the eye.
Cataracts have a light scattering effect so that light entering the eye through a wide angle is spread over the retina. This has an effect of reducing contrast of images viewed thus making such images appear blurred or out of focus. This is a particularly serious problem in higher light ambient conditions, such as on beaches and on days of bright sunshine. Also, at night, headlights of cars flood the eyes with light which affects normal eyes minimally when the eyes are directed to the road but which is scattered by cataracts and thus presents a problem to cataract patients wishing to drive at night.
To my knowledge, no optical device is presently available for pre-operative cataract patients which serves to improve vision markedly beyond that possible with prescription lenses alone while providing unrestricted field of vision horizontally and sufficient angle vertically for all practical needs. It has been proposed to produce spectacles with an array of apertures on an opaque background; for example, in U.S. Pat. No. 1,959,915. Such constructions, however, were designed for other purposes and would be unsatisfactory for use by pre-operative cataract patients who require maximum improvement of contrast while maintaining good mobility such as is needed for driving. Prior constructions such as disclosed in the cited patent admit too much light, especially from above where bright sources usually exist, while restricting horizontal vision which is critical for driving etc. Also, they fail to provide proper design for extending the field of good vision vertically which is needed for reading auto instruments, walking, etc. In fact, they tend to lead away from the unique combination of elements required by cataract patients.